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Biomedical subjects

G Caimi

Publications and source records attributed to G Caimi.

At least 19 recordsLinked to original sources
PubMed2004

Optical evidence for a spin-filter effect in the charge transport of Eu0.6Ca0.4B6.

We have measured the optical reflectivity R(omega) of Eu0.6Ca0.4B6 as a function of temperature (T) between 1.5 and 300 K and in external magnetic fields (H) up to 7 T. R(omega) increases with decreasing T and increasing H field, but the plasma edge feature does not exhibit the sharp onset and steep slope that is observed in EuB6. The analysis of the H-field dependence of the low-T optical conductivity confirms the previously observed exponential decrease of the electrical resistivity upon increasing bulk magnetization at constant T. The individual exponential magnetization dependences of the plasma frequency and scattering rate are also extracted from the optical data.

Journal Article↗
PubMed2004

Chronic renal failure: oxidative stress, endothelial dysfunction and wine.

Atherosclerosis development is accelerated in chronic renal failure (CRF) and is the major cause of death in this clinical condition. An increased oxidative stress and an endothelial dysfunction, with their complex interrelationships, are relevant aspects of atherogenesis in CRF patients and might be targets for treatment. Many studies have underlined the cardiovascular protection provided by a moderate wine consumption. This beneficial effect is due to both alcohol and nonalcoholic components of wine including several phenolic molecules such as quercetin and resveratrol. Wine polyphenols have antioxidant properties and favorably influence endothelial function, in particular by stimulating nitric oxide-mediated vasodilation and inhibiting the endothelin-1 pathway. The possible advantage of a moderate wine consumption in CRF patients can be hypothesized and deserves clinical investigation.

Cardiovascular Diseases↗
PubMed2004

Polymorphonuclear leukocyte: rheology, metabolism and integrin pattern in vascular atherosclerotic disease and in type 2 diabetes mellitus.

Leukocytes, and in particular polymorphonuclear cells (PMN), play a role in the organ injury that characterizes the progression of vascular atherosclerotic disease (VAD) and diabetes mellitus (DM). We enrolled subjects with VAD, subjects with type 2 DM (DM2) and subjects with VAD and DM2. We evaluated the initial relative flow rate (IRFR) of PMN, using the St. George Filtrometer, the PMN membrane fluidity, labelling intact PMN cells with the fluorescent probe 1.4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH), the PMN cytosolic Ca2+ content marking the cells with the fluorescent probe Fura 2-AM and the PMN integrin profile using the flow cytofluorimetry. All these evaluations were effected at baseline and after activation with 4-phorbol-12-myristate-13-acetate (PMA). At baseline and after activation the IRFR did not distinguish normal subjects from any group of patients. The PMN membrane fluidity at baseline differentiated only normal from DM2 subjects, while after activation no significant variation of this parameter was observed in normal, VAD, DM2 and VAD-DM2 subjects. The PMN cytosolic Ca2+ content, at baseline, discriminated only normal from VAD subjects with DM2, while after activation a significant increase of this parameter was evident in DM2 subjects and in VAD subjects with DM2. Regarding the PMN integrin pattern we observed, at baseline and after activation, a complex and non-univocal behaviour. In conclusion, the PMN rheological and metabolic pattern found in these groups of patients showed only small functional alterations while the integrin pattern was significantly different from that of normal subjects and added specific elements which may have potential therapeutical implications.

Arteriosclerosis↗
PubMed2004

Polymorphonuclear leukocyte membrane fluidity and cytosolic Ca(2+) content in young adults with acute myocardial infarction. Evaluation at the initial stage and after 12 months.

Our aim was to examine two aspects of polymorphonuclear leukocyte (PMN) rheology (membrane fluidity and cytosolic Ca2+ content), at baseline and after in vitro activation, in a group of young adults with acute myocardial infarction (AMI) at the initial stage and after 12 months. We enrolled 21 AMI subjects aged < or = 45 years (mean age 41.1 +/- 3.5 years) and evaluated PMN membrane fluidity, labelling intact PMN cells with the fluorescent probe 1,4-(trimethylamino)-phenyl-4-phenylhexatriene and the PMN cytosolic Ca2+ content marking PMN cells with the fluorescent probe Fura 2-AM, at baseline and after in vitro activation with 4-phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (fMLP). During the initial stage PMN membrane fluidity and cytosolic Ca2+ content did not distinguish AMI patients from control subjects; after 12 months, when compared with the initial stage, PMN cytosolic Ca2+ content was significantly increased. In vitro PMN activation with PMA and fMLP caused no variation of the two PMN parameters in control subjects, while in AMI patients membrane fluidity decreased and cytosolic Ca2+ content increased; the same behaviour pattern was observed after 12 months. The constant functional alteration of PMN cells in young AMI patients highlights the role of activated leukocytes as a component of the inflammatory reaction that follows ischemia.

Adult↗
PubMed2004

Genetic risk factors in myocardial infarction at young age.

The role of genetic susceptibility to coronary artery disease (CAD) seems to be quite important in young patients. In the last years the attention has been focused on polymorphisms influencing some biological functions (coagulation and fibrinolysis, platelets, vascular function, lipid metabolism, inflammation). The study of prothrombotic polymorphisms has kindled a deep interest. The role of atherosclerosis and thrombosis is different in the different ages. In all the studies we examined, the polymorphism G20210A in the prothrombin gene was associated with an increased risk of acute myocardial infarction (AMI) in young people, especially when other risk factors were present. Contradictory results have been found in the studies on Factor V Leiden: according to many authors the activated protein C resistance (APCR) is associated with an increased risk of AMI only in smokers, above all if women. On the other hand, some polymorphisms of the Factor VII gene seem to be protective. Young AMI could be also caused by a reduction of the fibrinolytic activity, as it was found when the allele 4G in the promoter of plasminogen activator inhibitor (PAI) gene is present. The attention has also been focused on the effects of variations in genes that influence platelet functions. According to a metanalysis of studies published up to 1999, there is no association between the polymorphism PlA1/A2 of the GP IIIa gene and young AMI, whereas there is doubt about the role of the polymorphism in the GP IIb e GP Ib genes. Moreover, it seems to be present an association with the polymorphisms in the thrombopoietin gene (C4830A and A5713G). Also the role of some genes coding for proteins influencing the vascular functions has been valued. Few studies were performed on genetics of the renin-angiotensin-aldosterone system and the results are insufficient and contradictory, such as those about the association between the polymorphism G894T in the eNOS gene or the polymorphism C677T in the MTHFR gene and young AMI. Genes coding for proteins involved in the lipid metabolism have been closely examined. Many polymorphisms were discovered in the Apo B gene: the variant C-516T was found to be associated with increased LDL levels, whereas the results about the association between this and other polymorphisms in the same gene (I/D of LAL sequence, PvuII, MspI, Asp4311Ser) and young AMI are discordant. On the other hand, the variant e4 of the ApoE gene was associated with an increased risk of AMI at young age in many works. In the last years, a particular interest has kindled the study of the relationship between inflammation, atherosclerosis and CAD. Even if the studies performed are few, it was found an association between young AMI and polymorphism C-260T in the CD14 gene, between coronarics atherosclerosis and polymorphism A516C in the E Selectin gene or polymorphisms Leu125Val and Ser563Asn in the PECAM1 gene.

Age of Onset↗
PubMed2003

Polymorphonuclear leukocyte integrin pattern, at baseline and after activation, in type 2 diabetic subjects with macrovascular complications.

In vascular atherosclerotic disease and in diabetes mellitus few studies have evaluated the polymorphonuclear leukocyte (PMN) adhesion molecule pattern. In this study we examined the PMN integrin expression at baseline and after activation in controls and type 2 diabetic subjects with macrovascular complications (MVC). We enrolled 21 subjects with type 2 diabetes mellitus and macrovascular complications, localized in peripheral, coronary and cerebral sites. The patients had peripheral occlusive arterial disease, chronic cerebrovascular disease or coronary heart disease. We evaluated the expression of some PMN integrins (CD11a, CD11b, CD11c, CD18), using flow cytofluorimetry, at baseline and after in vitro activation with 4-phorbol-12-myristate-13 acetate. Type 2 diabetic subjects with MVC showed, compared to normals, an increase of CD11a and CD18 and a decrease of CD11b and CD11c. After activation, in PMN(s) of normal subjects, we found an increase in the expression of all adhesion molecules, while in PMNS of type 2 diabetic subjects with MVC we observed an increase of CD11b and CD11c and a decrease of CD11a. In type 2 diabetic patients with MVC the basal upregulation of CD11a and CD18 may be related to the PMN spontaneous activation, while the behavior of CD11b may depend on its self-consumption. After activation the CD11a modification may be due to its cleavage or to an altered integrin phosphorylation/dephosphorylation balance.

Aged↗
PubMed2003

Diabetes mellitus: oxidative stress and wine.

This review focuses on the link between diabetes mellitus and oxidative stress and, in particular, on the role that moderate wine consumption may play in preventing diabetic complications and the onset of diabetes. With this aim, a search of PubMed was carried out for literature published up to March 2003. In diabetes mellitus, oxidative stress results both from exposure to hyperglycaemia through glycoxidation and sorbitol system activation, and from functional limitation of the hexose monophosphate shunt, leading to a decrease in glutathione synthesis. Oxidative stress alters the plasma lipoprotein profile (particularly low-density lipoproteins), the coagulative parameters (with an increased thrombotic risk), the endothelium (with a decrease in prostacyclin synthesis and an increase of thromboxane production) and the cell membranes (which undergo peroxidation). In diabetic patients, an altered oxidative pattern is present not only in the fasting state but also especially after food intake. In particular, food intake induces a decrease in the total radical-trapping antioxidant parameter (TRAP) and an elevation of hydroperoxides and thiobarbituric acid reactive substances (TBARS). Previously several clinical trials tried to improve the diabetic oxidative status using alpha-tocopherol, ascorbic acid and beta-carotene supplementation. Some authors found, in normal subjects, a reduction of hydroperoxides postprandially when the meal included red wine. Other authors showed that the oxidative pattern present in type 2 diabetic patients was mitigated by red wine. These actions may reduce cardiovascular risk. Moreover, an inverse relationship was observed between alcohol consumption and the incidence of type 2 diabetes; this relationship was valid for a light to moderate intake and it seemed to depend on drinking regularly and to be independent of the type of alcoholic beverage. In conclusion, moderate and regular wine consumption could ameliorate the diabetic oxidative status. This lifestyle measure might contribute to preventing diabetic complications and the onset of diabetes.

Antioxidants↗
PubMed2003

Haemorheological pattern in young adults with acute myocardial infarction.

Acute myocardial infarction (AMI) in young people has recently received great attention. Its main characteristics include a typical risk factor profile and a good prognosis. We studied the haemorheological pattern (whole blood viscosity at high and low shear rates, plasma and serum viscosity, whole-blood filtration and erythrocyte aggregation) in 64 subjects, aged <46 years, with recent AMI. We observed marked alterations in blood, plasma and serum viscosity and whole-blood filtration. Subdividing the AMI subjects in accordance with the number of cardiovascular risk factors or the extent of coronary lesions, we did not observe any significative influence of these aspects on the haemorheological determinants, with the exception of low shear rate blood viscosity. The latter was in fact higher than in control subjects only in AMI subgroups with respectively more risk factors and more stenosed coronary vessels. Thirty-three AMI subjects were re-examined after three months and showed, on this occasion, a haemorheological pattern not significantly different from that of the first evaluation. These results demonstrate that in young subjects with AMI there is a hyperviscosity syndrome that persists during subsequent months, despite a good clinical course. Haemorheological impairment may unfavourably influence the long-term prognosis of AMI in young subjects and therefore, in our opinion, management should take into account the monitoring of the haemorheological pattern.

Adult↗
PubMed2003

Wine and endothelial function.

In recent years many studies have focused on the well-known relationship between wine consumption and cardiovascular risk. Wine exerts its protective effects through various changes in lipoprotein profile, coagulation and fibrinolytic cascades, platelet aggregation, oxidative mechanisms and endothelial function. The last has earned more attention for its implications in atherogenesis. Endothelium regulates vascular tone by a delicate balancing among vasorelaxing (nitric oxide [NO]) and vasoconstrincting (endothelins) factors produced by endothelium in response to various stimuli. In rat models, wine and other grape derivatives exerted an endothelium-dependent vasorelaxing capacity especially associated with the NO-stimulating activity of their polyphenol components. In experimental conditions, reservatrol (a stilbene polyphenol) protected hearts and kidneys from ischemia-reperfusion injury through antioxidant activity and upregulation of NO production. Wine polyphenols are also able to induce the expression of genes involved in the NO pathway within the arterial wall. The effects of wine on endothelial function in humans are not yet clearly understood. A favorable action of red wine or dealcoholized wine extract or purple grape juice on endothelial function has been observed by several authors, but discrimination between ethanol and polyphenol effects is controversial. It is, however likely that regular and prolonged moderate wine drinking positively affects endothelial function. The beneficial effects of wine on cardiovascular health are greater if wine is associated with a healthy diet. The most recent nutritional and epidemiologic studies show that the ideal diet closely resembles the Mediterranean diet.

Animals↗
PubMed2002

Polymorphonuclear leukocyte membrane fluidity, at baseline and after in vitro activation, in obesity with or without diabetes mellitus.

We studied a group of 28 obese subjects (mean age 38.2+/-13.5 years, body mass index 35.0+/-5.6 kg/m2) with insulin resistance demonstrated employing an euglycemic hyperinsulinemic clamp, subdivided into a subgroup with normal glucose tolerance (NGT) and a subgroup with type 2 diabetes mellitus (DM). We examined the polymorphonuclear leukocyte (PMN) membrane fluidity at baseline and after activation with 4-phorbol 12-myristate 13-acetate (PMA) or N-formyl-methionyl-leucylphenylalanine (fMLP). At baseline, PMN membrane fluidity was significantly decreased in both subgroups compared to normals. In obese subjects with NGT no correlation was found between this PMN determinant and the parameters reflecting the insulin-resistance degree (glucose disposal [M] and metabolic clearance rate of glucose [MCR]), while in type 2 DM subjects the PMN membrane fluidity was correlated to M and MCR. After activation with PMA and fMLP, no variation in PMN membrane fluidity was observed in normals, while in obese subjects with NGT an early decrease was present only after fMLP activation, and in obese subjects with type 2 DM there was a constant and significant decrease of this PMN parameter after activation with PMA and fMLP. Our interest in the study of the PMN membrane fluidity emerges from its known role in PMN function, especially considering that PMN cells, together with monocytes, may be mediators of vascular damage.

Adult↗
PubMed2002

Haemorheological profile in metabolic Syndrome.

Metabolic Syndrome (MetS) has been defined as a clinical condition including impaired glucose tolerance or diabetes mellitus and/or insulin-resistance, associated with two or more of the following components: arterial hypertension, central obesity, dyslipidaemia, microalbuminuria. In a group of subjects with MetS we examined the macrohaemorheological profile, demonstrating a significant increase of blood, plasma and serum viscosity and a decrease of whole blood filterability. The results show that in these subjects a secondary hyperviscosity condition is present, but also that several significant correlations are present between the haemorheological variables and some aspects of MetS, especially those reflecting central obesity (waist to hip ratio) and insulin-resistance. The altered haemorheological profile likely contributes to explain the high cardiovascular risk present in MetS, but it may also participate, through its influence on haemodynamic pattern, in the pathogenesis of insulin-resistance.

Adult↗
PubMed2002

Polymorphonuclear leukocyte integrin profile in diabetes mellitus.

We examined the polymorphonuclear leukocyte (PMN) integrin pattern in 45 diabetic subjects without macrovascular complications, including 21 subjects with type 1 and 24 with type 2 diabetes mellitus. The PMN adhesion molecules (CD11a, CD11b, CD11c, CD18) were evaluated using indirect immunofluorescence and a flow cytometer, at baseline and after in vitro activation with 4-phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionyl-leucyl-phenyl-alanine (fMLP). At baseline, in diabetic subjects the phenotypical expression of CD11a and CD11b was significantly reduced and CD11c was increased, whereas CD18 was unchanged in comparison with normals. Considering type 1 and 2 diabetic subjects separately, CD11a was reduced and CD11c was increased in both subgroups, CD11b was decreased only in type 1 diabetics and CD18, decreased in type 1, was increased in type 2 subjects. After activation with PMA and fMLP, in normal subjects we observed a significant increase of all PMN adhesion molecules whereas in diabetic subjects only CD11c increased significantly with both activating agents, and CD11b increased only after PMA activation. In type 1 diabetic subjects only CD11c expression was increased, and in type 2 diabetic subjects an increase of CD11b (with PMA) and an increase of CD11c (with fMLP) were noted. In conclusion, we found in diabetic subjects of type 1 and 2 an altered behaviour pattern of PMN integrins both at baseline and, in particular, after in vitro activation. These data may help in explaining the role of PMN in the evolution of diabetic vascular complications.

Adult↗
PubMed2001

Granulocyte integrins before and after activation in acute ischaemic stroke.

We examined in 19 subjects with acute ischaemic stroke (AIS) the PMN integrin pattern (CD11a, CD11b, CD11c, CD18), using indirect immunofluorescence and adopting a flow cytometer, at baseline and during activation, prolonged for 5 and 15 min, with 4-phorbol 12-myristate 13-acetate (PMA). At baseline, an increase in the expression of CD11c and CD18 and a decrease in the CD11b were evident in AIS subjects compared to normals. After activation, we found in normals a constant and significant increase of all PMN adhesive molecules, while in AIS subjects, we found an increase in CD11b and CD18, a decrease in CD11a and no variation in CD11c. While the basal upregulation of CD11c and CD18 may depend on the PMN spontaneous activation or on the increase of cytokines, the decrease of CD11b may be due to its self-consumption. After activation, the decrease in CD11a noted in AIS may be related to its cleavage or to an altered integrin phosphorylation/dephosphorylation balance.

Acute Disease↗
PubMed2001

Leukocyte count, diabetes mellitus and age are strong predictors of stroke in a rural population in southern Italy: an 8-year follow-up.

Stroke incidence rates in the Mediterranean area are higher compared to northern European countries. In this study, we present the 8-year prospective data from a small rural Sicilian town. This population, consisting of 1351 subjects (622 males and 729 females), is homogeneous for ethnic background with traditional healthy dietary habits and shows low cholesterol mean levels. We found that the risk of stroke was significantly associated with the record of at least one previous neurological symptom (PNS), such as lack of strength, loss of vision or speech or possible drop attacks, and high hematocrit in males, and to high body mass index (BMI) and waist-hip ratio (WHR), diabetes, hypertension, high leukocyte count in females. We also documented age-related differences: stroke was associated in younger subjects (age<65 years) with diabetes, high BMI, high uric acid levels and in older patients (age>/=65 years) with high WHR, hypertension, diabetes, PNS, leukocyte count and hematocrit above the 95th percentile. Multivariate analysis demonstrated an independent association between stroke and age, diabetes, leukocyte count, hypertension and PNS. In conclusion, in this rural Sicilian population, the incidence rate of stroke is 1.72 cases per 1000/year in the subjects between 40 and 75 years of age. The risk factors associated with stroke are different in younger and older subjects. Leukocyte count, as an expression of an undergoing inflammatory process, may have a relevant role at least in the elderly.

Adult↗